Well established for the visible spectrum gaps of the transition metal dichalcogenide family,valleytronics—the control of valley charge and current by light—is comparatively unexplored for the THz gaps that characte...Well established for the visible spectrum gaps of the transition metal dichalcogenide family,valleytronics—the control of valley charge and current by light—is comparatively unexplored for the THz gaps that characterize graphene and topological insulators.Hereweshow that few cycle pulses of THz light can create and control a>90%valley polarized current in graphene,with lightwave control over the current magnitude and direction.This is underpinned by a light-matter symmetry breaking in the ultrafast limit of circularly polarized light,characterized by a symmetry lowering of the excited state charge distribution.Our findings both highlight the richness of few cycle light pulses in control over quantum matter,and provide a route towards a“THz valleytronics”in meV gapped systems.展开更多
基金funding through project-ID 328545488 TRR227(projects A04)Shallcrosswould like to thank DFG for funding through project-ID 522036409 SH 498/7-1+1 种基金Sharma and Shallcross would like to thank the Leibniz Professorin Program(SAW P118/2021)The authors acknowledge the North-German Supercomputing Alliance(HLRN)for providing HPC resources that have contributed to the research results reported in this paper.
文摘Well established for the visible spectrum gaps of the transition metal dichalcogenide family,valleytronics—the control of valley charge and current by light—is comparatively unexplored for the THz gaps that characterize graphene and topological insulators.Hereweshow that few cycle pulses of THz light can create and control a>90%valley polarized current in graphene,with lightwave control over the current magnitude and direction.This is underpinned by a light-matter symmetry breaking in the ultrafast limit of circularly polarized light,characterized by a symmetry lowering of the excited state charge distribution.Our findings both highlight the richness of few cycle light pulses in control over quantum matter,and provide a route towards a“THz valleytronics”in meV gapped systems.
